Hoists



Feb. 27, 1968 E. G. SPYRIDAKIS 3,370,832

HOIS'IS Filed Jan. 12, 1966 s Sheets-Sheet 1 INVENTOR EMANUEL 6. SPYR/DAK/S FIG. 2 I (QM musx E. G. SPYRIDAKIS Feb. 27, 1968 HOISTS 3 Sheets-Sheet 2 Filed Jan. 12, 1966 INVENTOR EMANUEL 6. SPYR/DAK/S ATTORNEY Feb. 27, 1968 E. G. SPYRIDAKIS 3,370,832

HOISTS Filed Jan. 12, 1966 3 Sheets-Sheet 5 FIG. 5

' INVENTOR EMANUEL a. SPYR/DAK/S Q M w Tm ATTORNEY Patented Feb. 27, 1968 3,370,832 HOISTS Emanuel G. Spyridakis, Athens, Pa., assignor to Ingersoll- Rand Company, New York, N.Y., a corporation of New Jersey Filed Jan. 12, 1966, Ser. No. 529,144 14 Claims. (Cl. 254-168) ABSTRACT OF THE DISCLOSURE An overhead hoist including a planetary gear train connected at one end to a power input means and at the other end to a load supporting means. The gear train is connected to a brake system by a cam means which locks the brakes to stop the gear train in response to stopping of the hoist. The planet gears are mounted on crowned splines which allow them to rock to automatically distribute the load uniformly on the teeth of the planet gears.

This invention relates generally to overhead hoists and particularly to driving systems and brakes for hoists.

Many conventional hoist driving systems containing planetary gear trains may be subjected to a non-uniform distribution of the load among the various meshed or engaged gear teeth on the gear train when the hoist is raising or holding heavy loads. As a result of the presence of non-uniform loads on the hoist gears, the gears must be unduly largeand heavy to withstand such loads and to resist wear on the gears. In turn, the use of larger gears increases the overall size, weight and cost of the hoist gear train.

A principal object of this invention is to provide a hoist driving system which eliminates or substantially minimizes the foregoing problem.

Another important object of this invention is to provide a planetary gear train containing means for uniformly distributing the load among the meshing gear teeth of the gear train under heavy loading conditions.

Still another object of this invention is to provide a hoist gear train which enables a substantial reduction in size and weight of a hoist.

Conventional hoist brakes require relatively high drive shaft torque for unlocking, thereby creating a tendency for the unbraked hoist mechanism and load to jump when the brake releases. This condition subjects the hoist and load to shock stresses. Even more important, most conventional hoist brake systems will allow the load to creep or drift under certain loading conditions.

Another important object of the present invention is to provide an overhead hoist with an improved load responsive brake.

A further object of the present invention is to provide an overhead hoist with a load responsive brake having means for low torque release and for preventing creeping or drifting of the load under all conditions.

The present invention contemplates an overhead hoist comprising a housing, a planetary gear train disposed in the housing connected at one end to a power input means and having a gear connected to a load supporting means,

a brake system disposed in the housing to prevent an ele' vated load from dropping when the hoist is at rest, a ring gear disposed in the housing in mesh with the planetary I gears and rotated through -a limited distance by the load while the hoist is at rest, and means for causing the ring gear to operate the brake system in response to limited rotation of the ring gear to frictionally lock the gear supporting the load. The planetary gear train contains means for allowingthe planet gears to rock for a limited extent and the planet gear frame to float for automatically distributing the load uniformly among the various meshing gear teeth in the planetary gear train. In addition, the brake system includes means for insuring the locking of the brakes under all conditions to prevent the load from drifting.

The invention is described in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view of a hoist embodying my invention;

FIG. 2 is a fragmentary axial section of the hoist of FIG 1;

FIGS. 3 and 4 are sectional end views taken on lines 3-3 and 44, respectively, of FIG. 2;

FIG. 5 is 'a fragmentary plan view of cooperating cam surfaces taken on line 55 of FIG. 2;

FIG. 6 is an enlarged fragmentary axial section of a planet gear of FIG. 2;

FIG. 7 is a fragmentary elevational view showing the connection between the cam-actuated ring gear and the brake rings, and

FIG. 8 is a fragmentary sectional view taken on line 8-8 of FIG. 7.

The hoist 1 shown in FIG. 1 includes a housing 2 formed of a gear casing 3 located at one end of the housing 2, a sprocket casing 4 located midway of the length of the housing 2, and a motor 5 located at the other end of the housing 2. A hook 6 is mounted on the top of the housing 2 for suspending the hoist 1. A hoist chain 7 extends through the sprocket casing 4 and carries a load hook 8 at one end for hoisting a load. As shown in FIG. 2, the chain 7 hangs on a sprocket 9 keyed on an output shaft 10. All of the foregoing structure is conventional. The specific details of the construction and assembly of the housing 2 is not described since they do not form any part of this invention.

DRIVE SYSTEM The motor 5 includes a drive shaft 12 which is interconnected by an internally splined sleeve 14 to an input drive shaft 15, as shown in FIG. 2. The outboard end of the input drive shaft 15 is mounted in bearings 16 carried by the end of the gear casing 3. The input drive shaft 15 carries an integral sun gear or pinion 17.

A planetary gear frame 20 is mounted over the input drive shaft 15 and carries three stub shafts 21 rotatably mounted in the gear frame 20 and spaced around the drive shaft 15 at equal radial distances from the drive shaft 15 and at an angular spacing of from each other. The stub shafts 21 are rotatably mounted in the gear frame 20 by bearings 22. The gear frame 20 is composed of two axially spaced end hubs 23 interconnected by three integral struts 24. The gear frame 20 further carries a ring 25 at each end hub 23 for engaging adjoining parts in the gear casing in a thrust bearing relationship to position and locate the gear frame 20 axially in the gear casing 3.

Each of the stub shafts 21 carries a pair of planet gears including a large planet 27 and a small planet 28. Each of the planet gears 27 and 28 are splined on the stub shaft 21 by a spline arrangement which allows the planets to rock slightly on the stub shaft 21. The provision of the rocking movement allows the planets 27 and 28 to automatically move to a properly aligned position with the mating gears in the drive train of the hoist. The large planet gear 27 meshes with the sun gear 17.

FIG. 6 illustrates the way that the planet gears 27 and 28 are mounted on the stub shaft 21 to permit the gears 27 and 28 to rock. Each of the gears 27 and 28 is provided with straight internal splines 30 and the stub shaft 21 carries splines 31 which are crowned along their length.

Due to the crowned profile on the splines 31, the straight splines 30 can tilt or rock along their length to a limited extent. In other words, the planet gears 27 and 28 can tilt or rock sideways on the stub shafts 21.

The small planet gears 28 engage an output ring gear 32 integrally mounted on the output shaft 10, which carries the hoist chain sprocket 9. The output shaft is rotatably mounted in a bearing 33.

The large planet gears 27 engage a large ring gear 35 which is mounted in the gear casing 3 for rotation through a small angle. Looking at FIG. 4, the large ring gear 35 is permitted to rotate a limited amount by having notches 36 engaging longitudinal rods 37 fixed in the gear casing 3. The notches 36 are somewhat wider than the diameter of the rods 37 so that the large ring gear 35 can rotate through a small angle.

In the foregoing planetary gear train, the sun gear 17 drives the large planet gears 27 which engages the relatively stationary large ring gear 35 resulting in the gear frame 20 rotating in the same direction as the sun gear 17. Due to the differential ratio between the planet gears 27 and 28 and their meshing ring gears 32 and 35, the small planet gears 28 will drive the output ring gear 32 in the same rotary direction as the gear frame 20 at a slower speed.

The gear frame 26 will float as it rotates, being supported in position by the planet gears 27 and 28 engaging the sun gear 17 and the ring gears 32 and 35. As a result, the gear frame 20 can move to a balanced position in the gear train. This floating ability of the gear frame 20, plus the ability of the planet gears 27 and 28 to rock will minimize non-uniform loading on the gear teeth. Reducing the non-uniform loading on the various gear teeth in the gear train reduces gear wear and the likelihood of gear tooth breakage and enables a reduction in the size and weight of the gear train, due to the absence of non uniform gear loads.

' HOIST BRAKE A hollow brake sleeve 40 surrounds the output shaft 19 with a one-way sprag clutch 41 interposed between the brake sleeve 40 and the output shaft 10. The sprag clutch 41 is arranged to lock the brake sleeve 40 to the output shaft 10 when the shaft 10 is rotating in a direction to lower a load. The sprag clutch 41 releases the brake sleeve 40 when the hoist is raising a load.

The circumference of the brake sleeve 40 carries splines 42 keyed to a series of brake discs 43, as shown in FIG. 3. The brake discs 43 are interleaved among a series of fixed discs 44 which are keyed to the rods 37 as shown in FIG.

'3. In this arrangement, the faces of each brake disc 43 are in frictional engagement with the faces of adjacent fixed discs 44. Preferably, the brake discs 43 are faced with a friction material such as might be used on a brake shoe or on a clutch face. The stack of interleaved brake and fixed discs 43 and 44 are located between a disc seat 45 fixed to the gear casing 3 and an annular brake plate 46 located at the other end of the stack.

The stationary ring gear 35 includes an extension flange 48 projecting longitudinally into engagement with the brake plate 46 whereby the ring gear 35 can move axially to clamp together the stack of brake discs 43 and fixed discs 44. The flange 48 carries a shoulder rib 49 engaging the brake plate 46 as shown in FIG. 2. Cam means is provided between the outboard end of the large gear 35 and the casing 3 to cam the ring gear 35 axially in a brake clamping direction when the ring gear 35 carries a rotary torque acting in a selected direction. This cam means comprises carn teeth 50 provided on the ring gear 35 engaging cam teeth 51 mounted on the gear casing 3 as shown in FIG. 5. The cam teeth 50 and 51 are arranged to cam the ring gear 35 axially in a brake engaging direction when the hoist is either raising a load or supporting a load in a stationary position. The cam means includes three pairs of the cam teeth 50 and 51 spaced at 120 around the ring gear 35 to provide the ring gear35 with a balanced axial camming force.

The brake plate 46 is keyed to the flange 48 of the ring gear 35, instead of being fixed to the gear casing 3. In addition, the fixed disc 52, located nearest to the brake plate 46, is key to the flange 48, instead of to the casing 3 as in the case of the fixed discs 44. This is accomplished by a series of tangs 54 projecting from the edge ofthe flange 48 and fitting in notches formed in the peripheries of the brake plate 46 and the fixed disc 52, as shown in FIG. 7.

When a torque acting in the clockwise direction (the load lowering direction) is applied to the output shaft 10, this torque is transmitted through the sprag clutch 41 to the brake sleeve 40 and the brake discs 43. Since the brake plate 46 and the fixed disc 52 are connected to the ring gear 35, instead of to the casing 3, the clockwise torque on the brake discs 43 will be transmitted to the ring gear 35 as soon as the'brake is slightly engaged by its cam means. This torque transmitted from the brake discs 43 through the brake plate 46 and fixed disc 52 to the ring gear 35 will aid in driving the ring gear 35 in the brake engaging direction. It has been found that this frictional torque applied to the ring gear 35 by the brake is necessary to insure that the brake will lock the hoist under all conditions when the hoist is stopped.

Otherwise, under certain conditions, when the hoist is lowering a load slowly and the operator stops the'hoist, it has been found that the load may coast or creep slightly before the brake is engaged sutficiently to stop the load. However, this torque applied to the ring gear 35 by the brake discs 43 is insufficient to prevent the brake from being released when the hoist is driven in a load lowering direction.

It is known that the additional torque, supplied by the feature of the brake plate 46 and fixed disc 52 being keyed to the ring gear 35, is unnecessary if the angle or slope on the cam teeth 50 and 51 is made relatively shallow or a gradual incline. However, if a small angle is provided to the cam teeth 50 and 51, the cam teeth 50 and 51 tend to lock together necessitating a relatively large force to unlock them which causes the hoist to move in jerks when lowering a load. V

On the other hand, when the cam teeth 50 and 51 are provided with a steeper slope, the locking tendency of the cam teeth is eliminated, but more torque is required to lock the ring gear 35 against moving; hence, the necessity for the additional torque provided by the keying of the brake plate 46 and the fixed disc 52 to the ring gear 35, as embodied in this invention. a

OPERATION In the following description of operation of the hoist, clockwise and counterclockwise rotation sets forth directions of rotation of the gear train as shown in FIGS. 3 and 4. It should be understood that the. output shaft 10 shown in FIG. 3 travels clockwise in lowering a load'and counterclockwise in raising a load. It should also be understood that rotation of the planet gears 27 and 28 by the sun gear .17 causes greater relative rotation between the fixed ring gear 35 and the gear frame 20 than between the output ring gear 32 and the gear frame, as a result of different gear ratios between the two ring gears 32 and 35 and their engaging planet gears 27 and 28. This difference in relative rotation between the gear frame 20 and the two ring gears 32 and 35 causes the output ringg'ear 32 to rotate slower than and in the same direction as the gear frame 20.

Under conditions where the hoist 1 is stationary with a load suspended on the hoist chain 7, the load will apply a torque on the output shaft 10 as shown in FIG. 3, acting in the clockwise direction. This torque will ur'ge'the planet gears 27 and 28 in a clockwise direction while the planet gears 27 apply a torque to the large ring gear 35 acting in a clockwise direction. This clockwise torque on the ring gear 35 causes the cam teeth 50 and 51 to react to force the ring gear 35 axially against the stack of brake discs, causing the brake discs to lock. At the same time, the sprag cltuch 41 locks together the output shaft and the brake sleeve 40. As a result of the foregoing actions, the output shaft 10 and sprocket 9 are locked against dropping. In case the output shaft 10 does rotate slightly in a clockwise direction, the frictional engagement between the brake plate 46, the fixed disc 52 and the brake disc 43 interposed between the above two members will apply a clockwise torque to the ring gear 35 sufficient to clamp the brake tighter.

In lowering a load, the motor 5 will drive the sun gear 17 in a clockwisedirection. This will cause the planet gears 27 and 28 to rotate in a counterclockwise direction and reaction with the large ring gear 35 will drive the gear frame in a clockwise direction while the large ring gear is urged in a counterclockwise direction to re lease the brake. As the motor 5 lowers a load, the load torque normally overruns the motor torque causing the brake to be alternately applied and released, which is usual in hoist brakes.

In raising a load, the motor 5 drives the sun gear 17 in a counterclockwise direction. This drives the planet gears in a clockwise direction and the reaction between the planet gears 27 and the fixed ring gear 35 drives the gear frame 20 in a counterclockwise direction. This movement of the gear frame 20 and its planets 27 and 2S drives the output shaft 10 in a counterclockwise direction. The sprag clutch 41 releases the output shaft 10 from the brake sleeve when the output shaft 10 rotates counterclockwise. As a result, the output shaft 10 is free to drive the sprocket 9 in the counterclockwise direction to raise the load.

Although a single embodiment of the invention has been illustrated and described, it should be understood that the invention is not limited thereto and that various changes may be made in the design and arrangement of the parts without departing from the spirit and scope of the invention.

Having described my invention, I claim:

1. In an overhead hoist having a power transmission housing and means disposed in the housing and extending therefrom for raising and lowering a load and supporting an elevated load, a power transmission and brake mechanism comprising:

a planetary gear train disposed in the housing and having a power input gear adapted to be rotatably driven, a power output gear connected to the load supporting means for raising a load when rotated in one direction and for lowering a load when rotated in the opposite direction, and planetary gear means interconnecting the power input and output gears for providing a driving connection therebetween;

brake means disposed in the housing and having friction means movable axially into and out of frictional engagement with one another; one of the friction means being connected against rotation to the housing and the other friction means being connected to the planetary gear system for rotation relative to said one of the friction means when the power output gear rotates in a direction to lower a load; brake gear means disposed in the housing for limited rotation between afirst and second position, and having cam means operable in response to the limited rotation for axial movement of the brake gear means away fiom said brake means to permit rotation of said other friction means when the brake gear means is rotated to'its first position and for causing the brake gear means to'move axially to- Wardly the brake means for moving the friction means into engagement with each other to hold the output gear from rotation when the brake gear means is rotated away from its first position and toward its second position;

the brake gear means being in mesh with the planetary gear means and rotated thereby toward its first position when the planetary gear means is rotated by the power input gear to lower the load and toward its second position when the power input gear is held against rotation and the power output gear is rotated by an elevated load; and

means interconnecting the brake gear means and brake means for causing said brake means to apply a small torque load on said brake gear means urging it toward its second position when said power output gear is supporting an elevated load.

2. The power transmission and brake means of claim 1, including:

means connecting the other friction means to theplanetary gear system to prevent relative rotation therebetween when the power output gear rotates in the direction to lower a load and to permit the power output gear to rotate relative to the other friction means in the direction to raise a load.

3. The power transmission and brake means of claim 1, wherein the planetary gear means comprises:

a gear frame rotatably located in the housing;

a cluster of gear means rotatably supported on the gear frame; and

each of the gear means of the cluster providing a pair of gear faces rotatable in unison and disposed axially relative to each other, one of which is in mesh with the power output gear and the other is in mesh with the power input gear and the brake gear means.

4. The power transmission and brake means of claim 3, wherein each of the gear means of the cluster comprises:

a rotatable shaft member having axial splines;

a pair of pinion members disposed on the shaft member in axial relation to one another each having splines in mesh with the splines of the shaft member to connect the pair of pinion members together for rotation in unison; and

one of the pair of pinion members meshing with the power output gear and the other of the pair of pinion members meshing with power input gear and the brake gear means.

5. The power transmission and brake means of claim 4 wherein:

the splines of one of each set of splines connected between the pinion and shaft members are crowned to permit the pinion members to rock on the shaft members for self-alignment and load distribution.

6. In an overhead hoist having a power transmission housing with a rotatable means disposed in one end of the housing and a hoist line means engaged by the rotatable means extending downwardly from the housing for raising and lowering a load when the rotatable means is rotated and for supporting an elevated load when the rotatable means is held against rotation, the combination of a power transmission and brake means comprismg:

a power input shaft disposed axially in the housing and adapted to be rotated to provide power to the hoist for raising and lowering loads;

a power input gear disposed in the housing and connected to the power input shaft for rotation thereby;

a ring gear disposed in the housing co-axial with the power input gear and having a tubular shaft portion encircling and extending axially along a portion of the power input shaft;

the rotatable means being connected to the tubular portion of the ring gear and rotated thereby for raising a load when rotated in one direction and for lowering a load when rotated in the opposite direction;

a plurality of rotatable gear means arcuately spaced one another each meshing with the power input and ring gears;

rotatable frame means disposed in the housing for supporting the rotatable gear means and revolving the rotatable gear means around the power input gear and within the ring gear when the frame means rotates;

the power input and ring gears with the meshing gear means and their frame means providing a gear train for transmitting rotational power from the power input shaft to the rotatable means;

friction means movable axially into and out of frictional engagement with each other for providing brake means in the housing to prevent a supported load from dropping, one of the friction means being fixed against rotation and the other of the pair of friction means being connected to the gear train for rotation relative to the one of the pair of friction means when the ring gear rotates in the direction for lowering'a load;

cam means fixedly disposed in the housing;

a brake gear disposed in the housing for limited rotation and being in mesh with the rotatable gear means and rotated thereby in one direction when the ring gear rotates to lower a load with the power input gear held against rotation and in the opposite direction when the ring gear rotates to lower a load in response to rotation of the power input gear;

the brake gear being movable axially toward and away from the brake means and having cam face means operatively associated with the cam means for moving' the brake gear axially toward the brake means when it is rotated in the one direction and for permitting the brake gear to move axially away from the brake means when it is rotated in the opposite direction; and

means disposed between the brake gear and brake means for causing said brake means to apply a small torque load on said brake gear urging it in said one direction when the ring gear is supporting a hoist load.

7. The power transmission and brake means of claim 6, including:

a unidirectional clutch disposed between the rotatable frame means and the other of the pair of axially movable friction means for connecting such friction means to each other for rotation in the direction of rotation of the frame means when the ring gear rotates to lower a load while the power input gear is held against rotation and for permitting the frame means to rotate in the opposite direction and relative to such other of the pair of axially movable friction means.

8. The power transmission and brake means of claim .6, wherein each of the rotatable gear means comprises:

a shaft member rotatably supported by the frame means and having axial splines;

a pair of pinion members disposed on the shaft in axial relation to one another with each having splines in mesh with the splines of the shaft member to connect the pair of pinion members to each other for rotation in unison; and

one of the pair of pinion members being in mesh with the ring gear and the other being in mesh with the power input and brake gears.

9. The power transmission and brake means in accordance with claim 8, and:

the meshing splines on one of the members of each connection between the pinion and shaft members being crowned to permit each of the pinion members to pivot on the shaft member for self-alignment and load distribution.

10. The power transmission and brake means in accordance with claim 9, and:

the meshing Splines being crowned to permit each of the pinion members to rock on the shaft member-forself-alignment and load distribution.

11. In an overhead hoist including a housing, a power transmission comprising:

a planetary gear train disposed in the housing and hav ing a power input gear adapted to be rotatably driven, a power output gear connected to a load supporting means for raising a load when rotated in one direction and for lowering a load when rotated in the opposite direction, and planetary gear means interconnecting the power input and output gears for providing a driving connection tlrerebetween;

said planetary gear means including-a rotatable frame;

a shaft member rotatably supported by the frame and having axial splines; 7

a pair of pinion members disposed on the shaft in axial relation to one another, each having splines in mesh with the splines of the shaft member to connect, the pair of pinion members together for rotation in unison; and 1 the meshing splines of one of the members of each connection between the pinion and shaft members being crowned to permit each of the pinion members to rock on the shaft member for self-alignment an load distribution.

12; The power transmission of claim 11 wherein said shaft member and pinion member are multiplied to provide said frame with a cluster of at least three planetary gears spaced around said frame; and

- said frame is supported solely by said cluster of planetary gears so that it is free to float for uniformly distributing the load on the gear teeth of said planetary gear train.

13. In planetary gearing having a rotatable frame-for supporting a cluster of planetary gear means, each of the gear means comprising:

a shaft member rotatably supported by the frame an having axial splines;

a pair of pinion members disposed on the shaft in axial relation to one another, each having splines in mesh with the splines of the shaft member to connect .the pair of pinion members together for rotation in unison; and p the meshing splines of one of the members of each connection between the pinion and shaft members being crowned to permit each of the pinion members to rock on the shaft member for self-alignment and load distribution. a

14. In planetary gearing having a rotatable frame for 50 supporting a cluster of planetary gear means, each of the gear means comprising:

a shaft rotatably supported by the frame and having axial splines; a pair of pinions disposed on the shaft in axial relation RICHARD E. AEGERTER, Primary Exahrine'rr 7O EVON C. BLUNK, Examiner.

H. c. HORNSBY, Assistant Examiner. 

